摘要
在对特定湍流条件下的水平轴潮流能水轮机进行数值模拟时,不同的湍流模型对于计算结果具有一定的影响。为选择合适的湍流模型对所设计水轮机的三维流场进行描述,将采用常用的两方程模型(SSTk-ω与Realizable k-ε)进行数值模拟,得到不同工况下水轮机的性能参数以及水轮机后1.5D处流场的流速、湍流强度分布情况,并进行模型水槽试验,试验值与采用两种湍流模型进行数值模拟得到的仿真值对比表明:在低尖速比工况下,采用SSTk-ω进行数值模拟得到的仿真值比Realizable k-ε更接近试验值,在较高尖速比时,采用Realizable k-ε进行模拟得到的数值更接近试验值;采用两种湍流模型进行数值模拟得到的速度分布具有相似性,但对于湍流强度的预测,SSTk-ω更具有优势。考虑此水轮机的实际工况,选择SSTk-ω湍流模型进行描述更加合理。
During the simulation towards horizontal axis tidal current energy turbine under the specific turbulent conditions,different turbulence models for calculation result has a certain impact.To choose suitable turbulence model for the description of the designed turbine'three-dimensional flow field,SST k-and Realizable k-εwere adopted to perform simulation,gaining the performance parameter of the turbine,flow velocity at the position of 1.5D after the turbine and turbulence intensity distribution.A model turbine was tested in flume.Comparison between the testing results and the simulation results with the two different turbulence models revealed that the simulation with SST k-turbulence model is more accurate than that with Realizable k-εturbulence model at the low tip speed ratio,the simulation with Realizable k-εturbulence model is more accurate than that with SST k-turbulence model at the high tip speed ratio.The velocity distribution gained by numerical simulation with different turbulence models is similar,but for the prediction of turbulence intensity,SST k-has more advantages.Considering the practical operating conditions of the turbine,SST k-turbulence model is more rational.
引文
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